What JohnDoeX thinks we are afraid to post

Ouch. They JDX down hard on the dot and the beard claim...
 
Take a gander at this thread over at PPrune, http://www.pprune.org/forums/showthread.php?t=245955 , for a comparison. This illustrates how actual pilots discuss technical issues and professionally debate even when they disagree. Only seven smilies are used in the whole thread. Seven smilies is a short post by JDX. It occurred to me that JDX has 43 posts per day at LC, and only 26 total posts since July at PPrune. After reading a few threads over there, it is now clear why.
 
Obviousman said:
I contacted a professional engineer who analyses FDR data for a living, and got him in touch with with DOH!

He looked at the data (.csv file) and said that because the altitude data was taken above Vmo, we don't know if it is accurate or not. He's had that pointed out time & time again, but he's won't give up his pet project.

Also, you are using pressure altitude data for something that requires RADALT data (which was not a valid parameter on the DFDR).

He hasn't looked at the DFDR itself, how it gained its inputs, what those senors were, what their tolerences were, what factors could affect the data, etc, etc.

He simply see what he wants to.
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Yup.

Alleged pilot Mr. DoeX's claim that this "makes a fool" out of Billzilla's analysis is entirely premature. Mr. DoeX is chickening out just when this gets interesting. In a real investigation, when two different analyses don't match, you have the potential to learn something useful. You tear apart both of them, examine their methods and assumptions, because somewhere somebody has made a mistake. If both approaches are reasonable on the surface, that means when you figure it out, everybody is about to learn something important.

Mr. DoeX's analysis, however, is not going to make that standard. Plainly missing from his work is any notion of calibration.

This is growing more and more common in CT's attempted derivations. We saw virtually the same mistake in the Ross and Furlong seismic paper. Their entire derivation was based on time records that they assumed were accurate to the second, and they showed "suspicious" discrepancies of up to 17 seconds. As it turned out, instead of reading event times, they were reading record start times. Since the Lamont-Doherty Earth Observatory at Columbia presents the events centered in 40-second windows to show background prior and following the events, there was a variable offset to the start of the event, varying from 0 to 20 seconds. This offset was their so-called "anomaly." Ross and Furlong never bothered to understand this, and Furlong got quite combative when this was pointed out to him. No calibration, no error estimation, thus no results.

Now we see Mr. DoeX making the same mistake. His tools are Flight Data Recorder records and positioning information from Google Earth. Are those sources calibrated? How accurate are they? He never even asks the question. The FDR is operating outside its range, so no, it's not calibrated, though some correction might be possible for someone much more technically minded. Google Earth? Don't make me laugh. That's not what it's designed to do. Errors of a few meters are not only possible, they're expected.

This is universal in science. It is possible to construct scientific experiments of mind-boggling precision, but only if you reciprocate with scientific rigor. One example that I have personally replicated as part of my training was devised by Millikan, one of the guiding fathers of my alma mater, and allows one to see with her own eyes the effect of a single electron. High-precision measurements require exceptional care.

The conspiracy set are almost doomed to fail in this regard. These legions of would-be Jupiter Joneses are so fixated on finding any anomaly, no matter how slight, that they'll challenge world governments upon finding a few seconds of error, or hearing a single unusual idiom ("Pull It"), or measuring a few meters -- as Mr. DoeX has done here.

While it may be possible to reduce the error of measurement in this flight path to a few meters, it cannot be done in such a haphazard fashion. It is simply impossible. Mr. DoeX has not estimated his error, and I doubt he has the first clue how to start. Or if he'd have any interest in doing proper work, work that might force him to change his mind.

Dear Conspiracy Theorists and budding writers of whitepapers, if you want to impress us, prepare an honest analysis. Estimate all sources of error, eliminate the ones that you can, declare the rest, and make your process transparent. Propagate your errors. Reference your work. If you don't know what I'm talking about, go to school until you do. If you actually do all this, then I promise you an honest response and genuine interest. If you don't, you're just another hack with delusions of grandeur and too many hours spent watching CSI.

You too, Mr. DoeX.
 
Estimate all sources of error, eliminate the ones that you can, declare the rest, and make your process transparent. Propagate your errors. Reference your work.
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It's so correct that it bears repeating. You have to model your error if you are going to base calculations on estimated numbers. You have to show that your answer (deviation from expectation) is statistically significant.
 
CptColumbo said:
A mod there (john_tullamarine) seems to have eliminated many of the posts in that thread.
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Any possibility that this stuff was archived somewhere on the net?

Love this bit:
Guys and gals .. Tech Log is not for this sort of infantile nonsense ... plenty of places elsewhere where folks can let their hair down a bit if that's the sort of thing which revs you up a tad .
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It's only in the very last post that we have an indication that the P finally came up in the conversation. Would REALLY love to read the posts when it finally did.
 
Well, I did some work. I was expecting to either find outright lies and fabrications in his numbers, or excepting a major precision error. I decided to reproduce his results, and then properly account for any error from the USGS, and see what I got.

These are HIS numbers (I have not checked them, I did look at the USGS, and the elevations match pretty closely with what they say, although i'd argue he tweaked it a few feet in his favor, but no big deal)

Pentagon at 38 feet above sea level.
Impact at 10 feet above that.
Base of LP#5 at 41 ft above sea level
Base of LP#4 at 42 ft above sea level
Base of LP#3 at 42 ft above sea level
Base of LP#2 at 45+20 ft above sea level (it's on an overpass)
Base of LP#1 at 45+20 ft above sea level (it's on an overpass)
Plane going 66ft/sec down, and 784 ft/sec. atan(66/784) = 4.8 degrees descent
Lightpoles are 40 feet high.

He didn't show his math for calculating the planes height, he just gave a number, so I decided to calculate this myself using google maps. In order to calculate you distance, the important factor is where the plane is, when it hits the lightpole so that is why I plotted the plane trajectory as a line, and measured along that line (using the normals given by the lightpoles).

Here is the image I used:

http://img137.imageshack.us/my.php?image=pentuy7.jpg

Here is a screen shot of my excel file, and my plot, including all the intermediete numbers. I'd upload the excel file if I had space, maybe at some later date.

http://img228.imageshack.us/my.php?image=pent3hu9.jpg

Here is the final plot, feel free to check my math...



Considering we both used the same inputs, the only reasonable conclusion is that one of us is bad at math. If it's me, I'll happily fix it.
 
R.Mackey said:
Yup.

Alleged pilot Mr. DoeX's claim that this "makes a fool" out of Billzilla's analysis is entirely premature. Mr. DoeX is chickening out just when this gets interesting. In a real investigation, when two different analyses don't match, you have the potential to learn something useful. You tear apart both of them, examine their methods and assumptions, because somewhere somebody has made a mistake. If both approaches are reasonable on the surface, that means when you figure it out, everybody is about to learn something important.

[snipped remainder]
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Nominated. You can expect the Men in Black to pay you a visit real soon.
 
Anti-sophist said:
Well, I did some work. I was expecting to either find outright lies and fabrications in his numbers, or excepting a major precision error. I decided to reproduce his results, and then properly account for any error from the USGS, and see what I got.

[...]

Considering we both used the same inputs, the only reasonable conclusion is that one of us is bad at math. If it's me, I'll happily fix it.
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Cool, a graph! And, more importantly, an attempt at reproducibility.

Do I understand from your writeup that you extrapolated trajectory from (a) point of impact and (b) the aircraft speed and rate of descent? Is it possible that the aircraft did not descend at a constant rate? How did you use the altimetry data?

I've argued in the other thread that the altimetry data error bars are large (I'm guessing ~ 40 m unless we can define the pressure altitude offset, in which case still ~ 20 m, but uncharacterized), but I haven't dug into it any further than that.
 
R.Mackey said:
Cool, a graph! And, more importantly, an attempt at reproducibility.

Do I understand from your writeup that you extrapolated trajectory from (a) point of impact and (b) the aircraft speed and rate of descent? Is it possible that the aircraft did not descend at a constant rate? How did you use the altimetry data?

I've argued in the other thread that the altimetry data error bars are large (I'm guessing ~ 40 m unless we can define the pressure altitude offset, in which case still ~ 20 m, but uncharacterized), but I haven't dug into it any further than that.
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I wouldn't trust the altitude data either for a variety of reasons(pneumatic lag, errors induced from exceeding Vmo)

On the other hand, Bill assures me that, at the speed AA77 was flying, the angle of attack to maintain level flight(deck angle) would be close to zero. Since we know the AoA(-4.9), couldnt we just use the sine of 4.9 degrees and multiply it by the distance the airplane travels in a second, at 463 kts - to get a rate of descent, then work backwards with the known lamp pole elevations and their distances from impact. This would eliminate the suspected bad variable - the pressure altitude.....
 
Yes, these calculations ignore the altimeter data (other than to compute the initial angle of descent). It works from the point of impact, assuming a linear trajectory. The final FDR blip, it should be noted, happened relatively close to pole #1.

I think I've found an error in my calculation that lets me repeat his numbers a little better, given all his data and assumptions. I'll post the corrections when I get home from work (Although, tonight is LOST and southpark, so it might be late).

Also, yes, he is assuming a constant rate of decent.
Some of the other undealt with issues;
1) Error in the elevation data (the site says +/- 7 to 15m)
2) Assumption of linear path (no acceleration)
3) Error in the final angle of attack (he finds this by assuming the average angle between the final two points of the FDR, and then using that angle for the last second).

The angle-of-descent error is pretty large, IF WE ASSUME A LINEAR trajectory. I got a standard deviation of 1.5 degrees.

If we don't assume a linear trajectory, it should be pretty easy to calculate an initial and final angle of descent, calculate the G forces, and the starting point (it's a quadratic). I'll probably do this later with a variety of reasonable numbers and see what happens.
 
Brainache said:
As someone else pointed out, he is using the FDR of flight 77 which was recovered from the wreckage of the pentagon to prove that flight 77 didn't hit the pentagon.
So I say; stupid or crazy- take your pick.
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To be consistent, he should say the flight data was faked, since he believes Flight 77 didn't hit the Pentagon.

But then we are left with the odd puzzle of why the conspirators faked flight infomation that proved the opposite of what they wanted people to believe, and then released it to the public.
 
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boloboffin said:
To be consistent, he should say the flight data was faked, since he believes Flight 77 didn't hit the Pentagon.
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To bend over backwards to be fair to JDX, he does say that the pressure altitude data proves that the FDR data was faked. He then refuses to put together a coherent scenario that explains the evidence he thinks he has, but falls back on the "hey, I'm just asking questions" schtick.
 
boloboffin said:
To be consistent, he should say the flight data was faked, since he believes Flight 77 didn't hit the Pentagon.

But then we are left with the odd puzzle of why the conspirators faked flight infomation that proved the opposite of what they wanted people to believe, and then released it to the public.
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Which brings us back to the typical CT notion that "They" are idiot savants. Omnipotent when it comes to fooling experts from around the world, yet so stupid that amateur sleuths on the internet can foil their plans.
 
Anti-sophist said:
Well, I did some work. I was expecting to either find outright lies and fabrications in his numbers, or excepting a major precision error. I decided to reproduce his results, and then properly account for any error from the USGS, and see what I got.

These are HIS numbers (I have not checked them, I did look at the USGS, and the elevations match pretty closely with what they say, although i'd argue he tweaked it a few feet in his favor, but no big deal)

Pentagon at 38 feet above sea level.
Impact at 10 feet above that.
Base of LP#5 at 41 ft above sea level
Base of LP#4 at 42 ft above sea level
Base of LP#3 at 42 ft above sea level
Base of LP#2 at 45+20 ft above sea level (it's on an overpass)
Base of LP#1 at 45+20 ft above sea level (it's on an overpass)
Plane going 66ft/sec down, and 784 ft/sec. atan(66/784) = 4.8 degrees descent
Lightpoles are 40 feet high.

He didn't show his math for calculating the planes height, he just gave a number, so I decided to calculate this myself using google maps. In order to calculate you distance, the important factor is where the plane is, when it hits the lightpole so that is why I plotted the plane trajectory as a line, and measured along that line (using the normals given by the lightpoles).


Considering we both used the same inputs, the only reasonable conclusion is that one of us is bad at math. If it's me, I'll happily fix it.
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Quickly looking over your chart. It doesnt look to scale. Your Xaxis for 200 feet is the same as the Y for 20 feet. Might have to back up those poles a bit?

Also, if you are using 66ft/sec and 784 ft/sec for the speed. If pole 1 was at 1050 feet away (roughly by looking at your chart), that would put the aircraft at over 1 second away. So about 85 feet above the impact hole at the pentagon? So we have 38 feet pentagon height, plus 10 feet impact hole height, plus 85 feet equals 133MSL when at pole 1. Is pole 1 higher than 133MSL?

Just some quick math I did based on your chart. I could be off a bit here and there.

I think I used to work with JDX, trying to find out. Im also checking over his work.
 
Weedwacker, JDX has flight 77 at 89 feet and descending at lightpole 5, which is approximately 500 feet from the Pentagon. At this point, given that the Pentagon is 77 feet' high and impact is approximately 0.64 seconds away, is it possible to do a flyover?
 
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